Tenancy by the entirety is a special form of joint tenancy that exists only between husband and wife.  It is a unitary title with each tenant having an equal right to the whole.  Although either a husband or wife may convey his or her interest in a tenancy by the entirety, the estate itself may not be severed or terminated by the conveyance.  Coraccio v. Lowell Five Cents Sav. Bank, 415 Mass. 145 (1993). 

So what type of estate (beyond a right to receive rents, products, income, profits, etc.) is conveyed when a husband or wife purports to convey his or her entire interest in the estate to a third person?  If a spouse conveys his or her interest to a third party, the third party acquires a defeasible estate subject to the other spouse's right of survivorship.  If the non-conveying spouse dies first, the third party owns 100% of the estate.  If the grantor-spouse dies first, the entire estate reverts to the non-conveying spouse and the third party is left with nothing.